To be honest I just throw in a mix of stuff after the main lift. Well, that's not entirely true --- on chest days I do one extra heavy exercise of either board presses or floor presses as well as DB tricep extensions. BB Rows and RDLs are staples on DL day. Lol - so I guess I have a few favorite/effective assistance exercises that I prefer to use as well as a handful of others that rotate in and out.

Of the assistance routines you mention they both look fun. For those not familiar with BBB or the Triumverate check out http://www.strstd.com/ and click on My 531 Routine then scroll down to where it says "Complete Routine with Accessory work"